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// ----------------------------------------------------------------------------
// Copyright (C) 2009 Sebastian Redl
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// For more information, see www.boost.org
// ----------------------------------------------------------------------------
#ifndef BOOST_PROPERTY_TREE_STREAM_TRANSLATOR_HPP_INCLUDED
#define BOOST_PROPERTY_TREE_STREAM_TRANSLATOR_HPP_INCLUDED
#include <boost/property_tree/ptree_fwd.hpp>
#include <boost/optional.hpp>
#include <boost/optional/optional_io.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/decay.hpp>
#include <boost/type_traits/integral_constant.hpp>
#include <sstream>
#include <string>
#include <locale>
#include <limits>
namespace boost { namespace property_tree
{
template <typename Ch, typename Traits, typename E, typename Enabler = void>
struct customize_stream
{
static void insert(std::basic_ostream<Ch, Traits>& s, const E& e) {
s << e;
}
static void extract(std::basic_istream<Ch, Traits>& s, E& e) {
s >> e;
if(!s.eof()) {
s >> std::ws;
}
}
};
// No whitespace skipping for single characters.
template <typename Ch, typename Traits>
struct customize_stream<Ch, Traits, Ch, void>
{
static void insert(std::basic_ostream<Ch, Traits>& s, Ch e) {
s << e;
}
static void extract(std::basic_istream<Ch, Traits>& s, Ch& e) {
s.unsetf(std::ios_base::skipws);
s >> e;
}
};
// Ugly workaround for numeric_traits that don't have members when not
// specialized, e.g. MSVC.
namespace detail
{
template <bool is_specialized>
struct is_inexact_impl
{
template <typename T>
struct test
{
typedef boost::false_type type;
};
};
template <>
struct is_inexact_impl<true>
{
template <typename T>
struct test
{
typedef boost::integral_constant<bool,
!std::numeric_limits<T>::is_exact> type;
};
};
template <typename F>
struct is_inexact
{
typedef typename boost::decay<F>::type decayed;
typedef typename is_inexact_impl<
std::numeric_limits<decayed>::is_specialized
>::BOOST_NESTED_TEMPLATE test<decayed>::type type;
static const bool value = type::value;
};
}
template <typename Ch, typename Traits, typename F>
struct customize_stream<Ch, Traits, F,
typename boost::enable_if< detail::is_inexact<F> >::type
>
{
static void insert(std::basic_ostream<Ch, Traits>& s, const F& e) {
#ifndef BOOST_NO_CXX11_NUMERIC_LIMITS
s.precision(std::numeric_limits<F>::max_digits10);
#else
s.precision(std::numeric_limits<F>::digits10 + 2);
#endif
s << e;
}
static void extract(std::basic_istream<Ch, Traits>& s, F& e) {
s >> e;
if(!s.eof()) {
s >> std::ws;
}
}
};
template <typename Ch, typename Traits>
struct customize_stream<Ch, Traits, bool, void>
{
static void insert(std::basic_ostream<Ch, Traits>& s, bool e) {
s.setf(std::ios_base::boolalpha);
s << e;
}
static void extract(std::basic_istream<Ch, Traits>& s, bool& e) {
s >> e;
if(s.fail()) {
// Try again in word form.
s.clear();
s.setf(std::ios_base::boolalpha);
s >> e;
}
if(!s.eof()) {
s >> std::ws;
}
}
};
template <typename Ch, typename Traits>
struct customize_stream<Ch, Traits, signed char, void>
{
static void insert(std::basic_ostream<Ch, Traits>& s, signed char e) {
s << (int)e;
}
static void extract(std::basic_istream<Ch, Traits>& s, signed char& e) {
int i;
s >> i;
// out of range?
if(i > (std::numeric_limits<signed char>::max)() ||
i < (std::numeric_limits<signed char>::min)())
{
s.clear(); // guarantees eof to be unset
e = 0;
s.setstate(std::ios_base::badbit);
return;
}
e = (signed char)i;
if(!s.eof()) {
s >> std::ws;
}
}
};
template <typename Ch, typename Traits>
struct customize_stream<Ch, Traits, unsigned char, void>
{
static void insert(std::basic_ostream<Ch, Traits>& s, unsigned char e) {
s << (unsigned)e;
}
static void extract(std::basic_istream<Ch,Traits>& s, unsigned char& e){
unsigned i;
s >> i;
// out of range?
if(i > (std::numeric_limits<unsigned char>::max)()) {
s.clear(); // guarantees eof to be unset
e = 0;
s.setstate(std::ios_base::badbit);
return;
}
e = (unsigned char)i;
if(!s.eof()) {
s >> std::ws;
}
}
};
/// Implementation of Translator that uses the stream overloads.
template <typename Ch, typename Traits, typename Alloc, typename E>
class stream_translator
{
typedef customize_stream<Ch, Traits, E> customized;
public:
typedef std::basic_string<Ch, Traits, Alloc> internal_type;
typedef E external_type;
explicit stream_translator(std::locale loc = std::locale())
: m_loc(loc)
{}
boost::optional<E> get_value(const internal_type &v) {
std::basic_istringstream<Ch, Traits, Alloc> iss(v);
iss.imbue(m_loc);
E e;
customized::extract(iss, e);
if(iss.fail() || iss.bad() || iss.get() != Traits::eof()) {
return boost::optional<E>();
}
return e;
}
boost::optional<internal_type> put_value(const E &v) {
std::basic_ostringstream<Ch, Traits, Alloc> oss;
oss.imbue(m_loc);
customized::insert(oss, v);
if(oss) {
return oss.str();
}
return boost::optional<internal_type>();
}
private:
std::locale m_loc;
};
// This is the default translator when basic_string is the internal type.
// Unless the external type is also basic_string, in which case
// id_translator takes over.
template <typename Ch, typename Traits, typename Alloc, typename E>
struct translator_between<std::basic_string<Ch, Traits, Alloc>, E>
{
typedef stream_translator<Ch, Traits, Alloc, E> type;
};
}}
#endif
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